Dental calculus is a mineralised deposit that forms on the surface of teeth. The mineralised deposit is largely crystals of calcium phosphate in various forms, in particular hydroxyapatite. It is desirable to prevent the formation of dental calculus by inhibition or retardation of hydroxyapatite crystal growth and also by inhibition of the transformation of more acidic forms of calcium phosphate (e.g. brushite) or amorphous calcium phosphate into hydroxyapatite.
Parran Jr. et al have specified the use of soluble inorganic alkalimetal pyrophosphates as anti-calculus agents in oral compositions. Reference is made to U.S. Pat. No. 4,515,772; U.S. Pat. No. 4,590,077 and U.S. Pat. No. 4,684,518.
In U.S. Pat. No. 4,534,881 Sikes et al disclose synthetically derived amino acid polymers for the inhibition or retardation of inorganic scaling where the synthetic polymers may contain phosphorylated amino acids. Further, in U.S. Pat. Nos. 4,866,161 and 4,868,287 to Sikes et al. have disclosed the use of synthetic polyamino acids for the control of dental calculus where the anionic amino acids are clustered at one end of the polypeptide with non-polar residues clustered at the other. The anionic amino acids are independently selected from phosphoserine, phosphohomoserine, phosphotyrosine, phosphothreonine, glutamate and aspartate. In European Patent Application 0,391,629, Sikes has disclosed synthetic polypeptides having a formula poly(X).sub.m (Y).sub.n where X is independently aspartate, glutamate, glutamine, asparagine or phosphoserine; each Y independently is a phosphorylated amino acid such as phosphoserine, phosphohomoserine, phosphotyrosine and phosphothreonine; m is 2 to 150; n is 1 to 3 and n+m is greater than or equal to 5.